We recently showed that venetoclax (ABT-199), a BCL2-selective inhibitor approved for relapsed or refractory chronic lymphocytic leukemia (CLL) with 17p deletion, efficiently induces apoptosis in patient-derived CTCL cells in vitro and this effect is synergistically potentiated by combination with HDAC inhibition [23, 24]. Here, HDAC9 is linked to B-cell chronic lymphocytic leukemia.